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THE RESPONSE OF SEEDS OF BROMUS STERILIS L. AND BROMUS MOLLIS L. TO WHITE LIGHT OF VARYING PHOTON FLUX DENSITY AND PHOTOPERIOD
Author(s) -
ELLIS R. H.,
HONG T. D.,
ROBERTS E. H.
Publication year - 1986
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1986.tb02915.x
Subject(s) - germination , photoperiodism , biology , bromus , population , botany , horticulture , poaceae , demography , sociology
S ummary The germination response of seeds of Brnmus mollis L. and B. sterilis L. to white fluorescent light was studied over a wide range of photon flux densities and photoperiods. Photon doses below 3 × 10 −3 mol m −8 d −1 had little effect on the percentage germination of either species, although in B. sterilis photon doses as low as 10 −4 mol m −2 d −1 depressed the rate of germination. An increase in photon dose above 10 −1 mol m −2 d −1 in B. mollis at 15 ° C C, 3 × 10 −3 mol m −2 d −1 in B. sterilis at 15 °C, and 3 × 10 −2 mol m −2 d −1 in B sterilis at 25 °C prevented the germination of an increasing number of seeds. The proportion of seeds which were inhibited showed a cumulative normal distribution with respect to the logarithm of photon dose. For a given photon dose, however, there was evidence that longer photoperiods were more inhibitory in both species: 24 h (continuous light) more than 8 h, and in fi sterilis 8 h more than 1 h. We conclude that the high irradiance reaction is the major cause of inhibition by white light in both species, but the sensitivity amongst the seeds within a population to photon dose varies by a factor of up to 10 5 . Amendments to seed‐testing procedures for B mollis are suggested.